Tension device for sewing-machine bobbins.



APPLICATION FILED MAY'II I914.

Patented IFGI). 5, 191%,

III:

rite.

JAMES LEATHEM, 0F LEBANON, PENNSYLVANIA, ASSIGNOR T0 HERRMANN AUKAM & (10., 'OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TENSION DEVICE FOR SEWING-MACHINE BOBBINS.

Application filed May 4, 1914.

To all whom it may concern:

Be it known that I, JAMEs Lnivrrimu, a citizen of the United States, and a resident of Lebanon, in the county of Lebanon and State of Pennsylvania, have invented certain new and useful Tension Devices for Sewing-Machine Bobbins, of whichthe following is a specification.

My invention relates to improvements in sewing machine bobbins and particularly to tension devices for such bobbins, and comprises a structure wherein a tension spring is mounted upon the top surface of the rim of a bobbin case and in cooperative proximity to said rim and to a thread-guiding slot; and in other features, all as hereinafter described and particularly pointed out in the appended claims.

The object of my invention is to improve sewing machine bobbins, particularly the tension device thereof.

I will now proceed to describe my invention with reference to the accompanying drawings and will then point out the novel features in claims.

In the drawings:

Figure 1 shows a top view of a sewing machine bobbin and bobbin case, the latter provided with my improved tension device, and of a rotary so-called hook or loop taker within which such bobbin and bobbin case are mounted.

Fig. 2 shows a side elevation of the same parts.

Fig. 3 shows a top view on a larger scale of the bobbin and bobbin case, removed from the hook.

Fig. 4t shows a side elevation of the same parts. i

Fig. 5 shows a transverse section of the bobbin and bobbin case on the line a2-m of Fig. 3.

In the drawings 1 designates the hook or loop taker. I do not claim such hook or loop taker herein, though the same possesses certain features of novelty claimed in a companion application, filed May 4, 1914, Sr. No. 836,167. For present purposes it may be considered that this hook or loop taker 1 is of ordinary construction.

2 designates the bobbin case which is a hollow cylindrical member adapted to receive the bobbin 3. The general construction of this bobbin case is covered in my prior Letters Patent 1,099,655, dated June 9,

Specification of Letters Patent.

Patented Feb. 5, 1919.

Serial No. 836,166.

1914, and therefore is not claimed herein. As is customary in sewing machines of the rotary loop taker type, this bobbin case is arranged to be held stationary while the hook or loop taker 1 rotates around it. Said bobbin case is provided at its upper edge with a projecting lip 4- which lip, as fully explained in my said Patent No. 1,099,655, engages a raceway in the interior of the loop taker 1, forming the support for the bobbin case. Upon the upper surface of this lip l is mounted a tension spring 5, secured to the lip of the bobbin case by two screws 6 and 7. As will be readily understood, by turning up the screw 7 the tension, or frictional retardation offered by the tension device to the passage of the thread, may be regulated.

The bobbin case 2 has in its side and extending from its lip l, diagonally downward and toward the right (as shown in Fig. 1) a thread slot, 8, terminating in an eye, 9. And the rim 4 has in it another thread slot 10 extending part way through the said rim in a direction nearly tangent to the inner edge of the bobbin case 2, underneath the ten sion spring 5 and terminating in an eye 11. 12 in Figs. 4 and 5, designates the bobbin thread. It will be understood by those skilled in the art, that the thread slot 8 in the bobbin case is provided to facilitate the threading of the bobbin case, i. e., the drawing of the bobbin thread into the'eye 9, and that the slot 10 is provided in the rim of the bobbin case to facilitate the drawing of the bobbin thread underneath the tension spring 5 and into the eye 11.

From the foregoing description, the method of threading the bobbin case will lie-understood readily. When inserting a loaded bobbin 3 into the bobbin case, the end portion of the bobbin thread will naturally be left extending somewhat from the bobbin; and this extending portion of the bobbin thread will be drawn through the thread slot 8 into the eye 9 and will then be drawn through the thread slot 10 into the eye 11, and underneath the tension spring 5. Such bobbin thread will then be pressed by the end portion of the spring 5 against the portion '13 of the lip 4 of the bobbin case, and thereby the desired tension action will be exerted upon the bobbin thread.

I-Ieretofore, in sewing machines employing rotary hooks, the tension device has porting flange or lip (at in the construction shown herein) of the bobbin case shall be as high as possible, 2'. e.,. shall be as far distant as possible from the base of the bobbin case.

v By'leading the bobbin thread up through thesaid flange at of the bobbin case, and by locating the tension device on the upper or top surface of this flange 4, the support for the bobbin case may be placed as far distant as possible from the base of the bobbin case, and at the same time all possibility of conflict of the bobbin thread with the support of the bobbin case is removed.

hat I claim is:

1., A bobbin case for rotary hook sewing machines, comprising an outer flange adjacent theutop of said bobbin case, a thread tension device situated on top of said flange but spaced away from the edge thereof, a

thread opening in said bobbin case and ineans for guiding the thread through said opening and beneath said tension device.

2, A bobbin case for rotary hook sewing machines comprising an outer bearing flange adjacent the top of said bobbin case, a thread tension device situated on top of said flange but spaced away from the edge thereof, said tension device tending to bear against the surface of said flange and having also thread guiding means arranged to guide thread between the said spring and the adjacent surface of the bobbin case.

A bobbin case for rotary hook sewing machines comprising an outer bearingtlange adjacent the top of said bobbin case. a thread tension device situated on top of said flange but spaced away from the edge thereof, said bobbin case having in its side a thread guiding opening, and in said flange another thread guiding opening laiding to said tension device.

4;. A bobbin case for rotary hook sewing machines comprising a rim and having a thread tension device on the top of its i'iin, having in its side a thread guiding opening and a thread slot, leading from the top of the bobbin case to such opening, and having in its rim a further thread guiding opening leading to said tension device.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

JAMES LEATH 1*) M.

Witnesses MARY R. Ross, J. W. Ross.

Copies of this patent may be obtained forfive cents each, by addressing the Commissioner of Patents,

I Washington, D. C. 

